In the prior art, the means for receiving a sound on the transmitter side and reproducing a sound field of the sound on the transmitter side has been proposed (see Patent Literatures 1 to 3). In such equipment, sound signals picked up by a plurality of microphones, etc. are transmitted, and the sound field on the transmitter side is reproduced by using a plurality of speakers on the receiver side. Such equipment possesses the advantage that a position of a talker can be specified by the sound.
In Patent Literature 1, the method of creating stereophonic sound information by transmitting sound information received by a plurality of microphone arrays and then outputting the sound information from speaker arrays of the same number as the microphone arrays to reproduce the sound field of the sender side, etc. are disclosed.
According to the method of Patent Literature 1, certainly it is possible to transmit the sound field itself on the sender side and specify a position of the talker by the sound. However, there existed such a problem that a lot of line resources must be used. Hence, another means for specifying position information of the talker and transmitting the information, etc. are disclosed (see Patent Literature 2, for example).
In Patent Literature 2, such an equipment is disclosed that, on the transmitter side, a voice of a talker is picked up by the microphone, then talker position information is generated by talker information obtained by the microphone, and then the talker position information is multiplexed with the voice information and transmitted, while the receiver side changes a position of the speaker that is caused to sound based on the talker position information transmitted such that the voice and the position of the talker is reproduced on the receiver side.
In Patent Literature 3, such a session equipment is set forth that, because it is not practical to cause all talkers to grip the microphone respectively, phases of the sound signals being input into respective microphones are shifted and synthesized by using a microphone controlling portion to specify the talker. In Patent Literature 3, the phase pattern to give the maximum sound is decided by changing the phase shift pattern corresponding a seat position of the talker, and then a position of the talker is specified based on the decided phase shift pattern.
In the talk session equipment (the sound emitting/collecting apparatus) in Patent Literature 4, the sound signal input via the network is emitted from speakers arranged on the top surface, and sound signals picked up by respective microphones which are arranged on the side surface and whose front faces are set in plural different directions respectively are transmitted to the outside via the network.
Also, in the home announce equipment (the sound emitting/collecting apparatus) in Patent Literature 5, the talker direction is detected by applying a delay process to sound collecting signals from respective microphones of the microphone array respectively, and a volume of sounds emitted from the speakers adjacent to this talker is reduced.
Patent Literature 1: JP-A-2-114799
Patent Literature 2: JP-A-9-261351
Patent Literature 3: JP-A-10-145763
Patent Literature 4: JP-A-8-298696
Patent Literature 5: JP-A-11-55784